Paper Title:

Effect of Aggregate on Drying Shrinkage of Concrete

Periodical Advanced Materials Research (Volumes 168 - 170)
Main Theme Advances in Building Materials, ICSBM 2011
Edited by Lijuan Li
Pages 701-708
DOI 10.4028/www.scientific.net/AMR.168-170.701
Citation Ru Mu et al., 2010, Advanced Materials Research, 168-170, 701
Online since December 2010
Authors Ru Mu, Wen Ling Tian, Yong Gang Guo
Keywords Concrete, Deformation, Diffusion, Shrinkage
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A modified version of an existing drying shrinkage model developed by the authors is proposed which incorporates the influence of the aggregate on the process of shrinking. Whereas it is traditionally thought that the aggregate restrains the deformation of the cement paste and hence the shrinkage of the concrete, in this paper, the effect of aggregate on shrinkage is better represented by considering the effect of the aggregate on moisture diffusion. It is suggested that the presence of the aggregate modifies the diffusion of moisture which governs the moisture loss and hence the drying of concrete. Also, as the volume fraction of the aggregate in a normal concrete is about 75% or more, the shrinkage of the cement paste is ‘diluted’ by the aggregate in the concrete. Taking into account these effects, this new diffusion based shrinkage model has been proposed. To assess the accuracy of the new model the shrinkage of two concrete mixes is predicted and compared with the measured shrinkage of these mixes. Comparisons are also drawn with the shrinkage predicted using the Model Code 1990 (MC90). It was observed that the new model proposed here predicts the shrinkage of the concrete mixes more accurately than the MC90 model, particularly at early ages.